What are the best ways to work out your fuel/tyre strategies

What is the best way to work out how much fuel you need for your races. Before I took a break from iGP, I decided that to work out my fuel, I should do litres per laps * amount of laps / thoughts on how many stops needed.

An example of this could be a 50% race in Monaco. So you will go 2.8 litres per lap (going off what my tech director says) * 39 laps / 2 (Stops I predict I'll need). But I don't think that is the right way.

Tyres is also another problems knowing what compound to use 

if anybody has got any ideas on how to work a good fuel/tyre strategy out, I would love to know

It all depends...
When i started, i often watched other people races, to see what tyres they used, how many stops they make, ask the fuel usage and so on.
That helped me a lot.
Then, im my races i compared my strategies with the ones who finished in the top places. Learned more...
Then when i was equal to them i started to think how could i improve/overcome their strategies (by stopping later, had more/less stops, choose other tyres, etc).

Now i always know what do do to have good results...(sometimes still have doubts...lol)
I've made a excel spreadsheet to help me with the strategies i want for any given race. You can find it here:
http://igpmanager.com/play/?url=forum-thread_5/702#31553

Hope it helps you.

How does it work, it does look a bit confusing at first glance of it?

Just see some posts above (page 3 or 4)... there's a explanation to it, althought i've changed it a bit, it's still the same mechanism...

ah right, cheers

Sorry, Richard, it's on page 5, it's #81 under manager Ricardo Patrese (it's me too).
If you still have questions, please ask, i'm glad to help...

haha, I already got the info needed. going to put it into a document so i dont forget how to use it :D. Once again though, thanks for the spreadsheet, should help me get some good results once I get the hang of it and get back into the swing of iGP after taking a few months off for personal reasons